I am retired and I collect 2 pensions and social security, do I have to file taxes?

Yes you probably have to file.  If your pensions are more than $4,200 for the whole year then nobody can claim you.  And if the pensions or social security take out any tax withholding you do want to file in case you get it back as a refund.  And depending on your total income part of your SS might be taxable.

Do I need to file a return?
https://ttlc.intuit.com/community/filing-and-paying-taxes/help/do-i-need-to-file-a-federal-return-this-year/00/25546

If you are single, you must file if your taxable income is more than $12,200 (or $13,850 if you are age 65 or older).  Social security is not taxable until your other income is more than $25,000, but your pensions are taxable.  

If your taxable income is more than $4200, no one can claim you as a dependent.

Your daughter could deduct medical expenses she pays for you on her tax return even though you are not her tax dependent, if she pays more than half your total living costs.